Deoxyribonucleic Acid Base Composition and Biochemical Properties of Certain Coagulase-Negative Enterotoxigenic Cocci

Aims: The objective of this study was to investigate the detection of SEE, SEG, SEH and SEI in strains of Staphylococcus aureus and coagulase‐negative staphylococci (CNS) using RT‐PCR. Methods and Results: In this study, 90 Staph. aureus strains and 90 CNS strains were analysed by PCR for the detection of genes encoding staphylococcal enterotoxins (SE) E, G, H and I. One or more genes were detected in 54 (60%) Staph. aureus isolates and in 29 (32·2%) CNS isolates. Staphylococcus epidermidis was the most frequently isolated CNS species (n = 64, 71·1%), followed by Staphylococcus warneri (n = 8, 8·9%) and other species (Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus lugdunensis, Staphylococcus simulans, Staphylococcus saprophyticus and Staphylococcus xylosus: n = 18, 20%). The genes studied were detected in Staph. epidermidis, Staph. warneri, Staph. haemolyticus, Staph. hominis, Staph. simulans and Staph. lugdunensis. The highest frequency of genes was observed in Staph. epidermidis and Staph. warneri, a finding indicating differences in the pathogenic potential between CNS species and highlighting the importance of the correct identification of these micro‐organisms. RT‐PCR used for the detection of mRNA revealed the expression of SEG, SEH and/or SEI in 32 (59·3%) of the 90 Staph. aureus isolates, whereas expression of some of these genes was observed in 10 (34·5%) of the 90 CNS isolates. Conclusions: Staphylococcus epidermidis was the most toxigenic CNS species. Among the other species, only Staph. warneri and Staph. lugdunensis presented a positive RT‐PCR result. PCR was efficient in confirming the toxigenic capacity of Staph. aureus and CNS. Significance and Impact of the Study: This study permitted to confirm the toxigenic capacity of CNS to better characterize the pathogenic potential of this group of micro‐organisms. In addition, it permitted the detection of SEG, SEH and SEI, enterotoxins that cannot be detected by commercially available immunological methods.

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“…aureus mutants that do no express the coagulase enzyme (Victor et al. 1969; Lotter and Genigeorgis 1975; Fox et al. 1996).…”

Section: Discussionmentioning

confidence: 99%

Molecular detection of enterotoxins E, G, H and I in Staphylococcus aureus and coagulase-negative staphylococci isolated from clinical samples of newborns in Brazil

Vasconcelos

Pereira

Júnior

et al. 2011

Journal of Applied Microbiology

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“…lentus species ). Lotter & Genigeorgis (1975) and Gramoli & Wilkinson (1978) also reported the incidence of staphylococci from various sources which were difficult to classify. Whilst, however, the characteristics of the strains of coagulasenegative staphylococci described here differs from those mentioned in the literature (Kloos et a/.…”

Section: Discussionmentioning

confidence: 99%

Characteristics of some unclassifiable strains of staphylococci isolated from goats and sheep

Adegoke

1985

Journal of Applied Bacteriology

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Fourteen strains of catalase-positive, Gram-positive and coagulase-negative cocci that were sensitive to 20 micrograms/ml of furazolidone were isolated from goats and sheep. Two of the strains had glycerol with glucose teichoic acids whilst another possessed glycerol, glucose, glucosamine and acetylglucosamine teichoic acids. Six strains had peptidoglycan type L-Lys-Ala-Gly4 peculiar to Staphylococcus sciuri and Staph. lentus but other phenotypic characters were different from those of Staph. sciuri and Staph. lentus. The guanine plus cytosine (G + C) content of the DNA determined for three of the strains examined ranged from 32.9-34.6 mol %. The coagulase-positive staphylococcal strain of caprine origin examined had glycerol and glucosamine teichoic acids in addition to peptidoglycan type L-Lys-Gly5-6. The characteristics of the strains of staphylococci described herein are different from those already described in the literature.

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“…Strain FRI-698 was examined by Lotter and Genigeorgis (29) is their study of coagulasenegative variants of S. aureus. The isolate they used was coagulase-negative and positive for delta hemolysin, egg yolk reaction, thermonuclease, penicillinase, phosphatase, acetoin, protein A, acid from maltose, and production of enterotoxin D and pigment.…”

Section: Discussionmentioning

confidence: 99%

Characterization of staphylococci

Hoover¹,

Tatini²,

Maltais³

1983

Appl Environ Microbiol

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A total of 158 Staphylococcus strains from various sources were characterized by biochemical, physiological, and morphological tests. Numerical taxonomy was applied by using these features. Taxonomic analysis was done with programs run under the MVS-TSO system of the IBM 370 complex and PDP-10 system of the National Institutes of Health. DNA-DNA hybridization with nitrocellulose filters was done to compare selected atypical cultures with American Type Culture Collection reference strains. We found that the use of the nomenclature of Bergey's Manual (8th edition) to identify these strains by species was not adequate. DNA homology values supported the formation of Staphylococcus hyicus subsp. hyicus separate from Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus saprophyticus. The three tests that best separated these strains into four species were (i) tube coagulase (6-h or 24-h porcine plasma or 24-h Difco rabbit plasma), (ii) production of acetoin or acid aerobically from ribose, maltose, or trehalose, and (iii) growth in the presence of novobiocin. Four strains of S. hyicus subsp. hyicus (VII76, VII113, VII131, and VA519) gave typical enterotoxigenic responses in monkey-feeding tests but were negative for enterotoxins A through E, suggesting the presence of one or more new enterotoxins. Two coagulase-negative, heat-stable DNase-positive strains (D143 and ARM) could not be classified by either DNA-DNA hybridization or numerical taxonomy, and D143 was enterotoxigenic as measured by the monkey-feeding bioassay. DNA homology showed that strain FRI-698M was more closely related to S. epidermidis than to S. aureus, yet it produced enterotoxin D. These data suggest the occurrence of coagulase-negative enterotoxigenic strains that are not S. aureus; nonetheless, a positive tube coagulase test and heat-stable DNase test should together be useful for routine screening of most potentially enterotoxigenic staphylococci in foods.

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Deoxyribonucleic Acid Base Composition and Biochemical Properties of Certain Coagulase-Negative Enterotoxigenic Cocci

Cited by 15 publications

References 17 publications

Molecular detection of enterotoxins E, G, H and I in Staphylococcus aureus and coagulase-negative staphylococci isolated from clinical samples of newborns in Brazil

Molecular detection of enterotoxins E, G, H and I in Staphylococcus aureus and coagulase-negative staphylococci isolated from clinical samples of newborns in Brazil

Characteristics of some unclassifiable strains of staphylococci isolated from goats and sheep

Characterization of staphylococci

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